<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>
  <script>
    function Foo() {
      getName = function () {
        console.log(1);
      }
      return this;
    }

    Foo.getName = function BBB() {
      console.log(2);
    }

    Foo.prototype.getName = function AAA() {
      console.log(3);
      return this;
    }

    var getName = function () {
      console.log(4)
    }

    function getName() {
      console.log(5)
    }

    Foo.getName(); //2
    getName(); //4
    Foo().getName(); //1
    getName(); //1

    new Foo.getName(); //2
    new Foo().getName(); //3
    let a = new new Foo().getName(); //3
    console.log(a);
  </script>
</body>

</html>